Vitamin B12-Impaired Metabolism Produces Apoptosis and Parkinson Phenotype in Rats Expressing the Transcobalamin-Oleosin Chimera in Substantia Nigra

International audienceThe development of fearfulness and the capacity of animals to cope with stressful events are particularly sensitive to early experience with mothers in a wide range of species. However, intrinsic characteristics of young animals can modulate maternal influence. This study evaluated the effect of intrinsic fearfulness on non-genetic maternal influence. Quail chicks, divergently selected for either higher (LTI) or lower fearfulness (STI) and from a control line (C), were cross-fostered by LTI or STI mothers. Behavioural tests estimated the chicks' emotional profiles after separation from the mother. Whatever their genotype, the fearfulness of chicks adopted by LTI mothers was higher than that of chicks adopted by STI mothers. However, genetic background affected the strength of maternal effects: the least emotional chicks (STI) were the least affected by early experience with mothers. We demonstrated that young animal's intrinsic fearfulness affects strongly their sensitivity to non-genetic maternal influences. A young animal's behavioural characteristics play a fundamental role in its own behavioural development processes

Anchoring Secreted Proteins in Endoplasmic Reticulum by Plant Oleosin: The Example of Vitamin B12 Cellular Sequestration by Transcobalamin

BACKGROUND: Oleosin is a plant protein localized to lipid droplets and endoplasmic reticulum of plant cells. Our idea was to use it to target functional secretory proteins of interest to the cytosolic side of the endoplasmic reticulum of mammalian cells, through expressing oleosin-containing chimeras. We have designed this approach to create cellular models deficient in vitamin B12 (cobalamin) because of the known problematics associated to the obtainment of effective vitamin B12 deficient cell models. This was achieved by the overexpression of transcobalamin inside cells through anchoring to oleosin. METHODOLOGY: chimera gene constructs including transcobalamin-oleosin (TC-O), green fluorescent protein-transcobalamin-oleosin (GFP-TC-O) and oleosin-transcobalamin (O-TC) were inserted into pAcSG2 and pCDNA3 vectors for expression in sf9 insect cells, Caco2 (colon carcinoma), NIE-115 (mouse neuroblastoma), HEK (human embryonic kidney), COS-7 (Green Monkey SV40-transfected kidney fibroblasts) and CHO (Chinese hamster ovary cells). The subcellular localization, the changes in vitamin B12 binding activity and the metabolic consequences were investigated in both Caco2 and NIE-115 cells. PRINCIPAL FINDINGS: vitamin B12 binding was dramatically higher in TC-O than that in O-TC and wild type (WT). The expression of GFP-TC-O was observed in all cell lines and found to be co-localized with an ER-targeted red fluorescent protein and calreticulin of the endoplasmic reticulum in Caco2 and COS-7 cells. The overexpression of TC-O led to B12 deficiency, evidenced by impaired conversion of cyano-cobalamin to ado-cobalamin and methyl-cobalamin, decreased methionine synthase activity and reduced S-adenosyl methionine to S-adenosyl homocysteine ratio, as well as increases in homocysteine and methylmalonic acid concentration. CONCLUSIONS/SIGNIFICANCE: the heterologous expression of TC-O in mammalian cells can be used as an effective strategy for investigating the cellular consequences of vitamin B12 deficiency. More generally, expression of oleosin-anchored proteins could be an interesting tool in cell engineering for studying proteins of pharmacological interest

Luminal expression of cubilin is impaired in Imerslund-Gräsbeck syndrome with compound AMN mutations in intron 3 and exon 7

Juvenile megaloblastic anaemia 1 (OMIM # 261100) is a rare autosomic disorder characterized by selective cobalamin mal-absorption and inconstant proteinuria produced by mutations in either CUBN or AMN genes. Amnionless, the gene product of AMN, is a transmembrane protein that binds tightly to the N-terminal end of cubilin, the gene product of CUBN. Cubilin binds to intrinsic factor-cobalamin complex and is expressed in the distal intestine and the proximal renal tubule. We report a compound AMN heterozygosity with c.742C>T, p.Gln248X and c.208-2A>G mutations in 2 siblings that led to premature termination codon in exon 7 and exon 6, respectively. It produced a dramatic decrease in receptor activity in urine, despite absence of CUBN mutation and normal affinity of the receptor for intrinsic factor binding. Heterozygous carriers for c.742T and c.208-2G had no pathological signs. These results indicate that amnionless is essential for the correct luminal expression of cubilin in humans

Exome-Wide Association Study Identifies New Low-Frequency and Rare UGT1A1 Coding Variants and UGT1A6 Coding Variants Influencing Serum Bilirubin in Elderly Subjects

International audienceGenome-wide association studies (GWASs) have identified loci contributing to total serum bilirubin level. However, no exome-wide approaches have been performed to address this question. Using exome-wide approach, we assessed the influence of protein-coding variants on unconjugated, conjugated, and total serum bilirubin levels in a well-characterized cohort of 773 ambulatory elderly subjects from Italy. Coding variants were replicated in 227 elderly subjects from the same area. We identified 4 missense rare (minor allele frequency, MAF < 0.5%) and low-frequency (MAF, 0.5%–5%) coding variants located in the first exon of the UGT1A1 gene, which encodes for the substrate-binding domain (rs4148323 [MAF ¼ 0.06%; p.Gly71Arg], rs144398951 [MAF ¼ 0.06%; p.Ile215Val], rs35003977 [MAF ¼ 0.78%; p.Val2 25Gly], and rs57307513 [MAF ¼ 0.06%; p.Ser250Pro]). These variants were in strong linkage disequilibrium with 3 intronic UGT1A1 variants (rs887829, rs4148325, rs6742078), which were significantly associated with total bilirubin level (P ¼ 2.34 Â 10 À34 , P ¼ 7.02 Â 10 À34 , and P ¼ 8.27 Â 10 À34), as well as unconjugated, and conjugated bilirubin levels. We also identified UGT1A6 variants in association with total (rs6759892, p.Ser7Ala, P ¼ 1.98 Â 10 À26 ; rs2070959, p.Thr181Ala, P ¼ 2.87 Â 10 À27 ; and rs1105879, p.Arg184Ser, P ¼ 3.27 Â 10 À29), unconjugated, and conjugated bilirubin levels. All UGT1A1 intronic variants (rs887829, rs6742078, and rs4148325) and UGT1A6 coding variants (rs6759892, rs2070959, and rs1105879) were significantly associated with gallstone-related cholecystectomy risk. The UGT1A6 variant rs2070959 (p.Thr181Ala) was associated with the highest risk of gallstone–related cholecystectomy (OR, 4.58; 95% CI, 1.58–13.28; P ¼ 3.21 Â 10 À3). Using an exome-wide approach we identified coding variants on UGT1A1 and UGT1A6 genes in association with serum bilirubin level and hyperbilirubinemia risk in elderly subjects. UGT1A1 intronic single-nucleotide polymorphisms (SNPs) (rs6742078, rs887829, rs4148324) serve as proxy markers for the low-frequency and rare UGT1A1 variants, thereby providing mechanistic explanation to the relationship between UGT1A1 intronic SNPs and the UGT1A1 enzyme activity. UGT1A1 and UGT1A6 variants might be potentially associated with gallstone-related cholecystectomy risk. (Medicine 94(22):e925) Abbreviations: 3D = three-dimensional, 95% CI = 95% confidence interval, EM = expectation-maximization, GWAS = genome-wide association study, HWE = Hardy–Weinberg equilibrium, IBD = identity by descent, LD = linkage disequilibrium, MAF = minor allele frequency, MRP2 = multidrug resistance-associated protein 2, OR = odds ratio, PCA = principal-component analysis, SNP = single nucleotide polymorphism, UGT1A1 = UDP-glucuronosy-ltransferase 1 family, polypeptide A1, UGT1A6 = UDP-glucuro-nosyltransferase 1 family, polypeptide A6

Next-generation sequencing and genotype association studies reveal the association of HLA-DRB3*02:02 with delayed hypersensitivity to penicillins.

Nonimmediate (delayed)-allergic reactions to penicillins are common and some of them can be life-threatening. The genetic factors influencing these reactions are unknown/poorly known/poorly understood. We assessed the genetic predictors of a delayed penicillin allergy that cover the HLA loci. Using next-generation sequencing (NGS), we genotyped the MHC region in 24 patients with delayed hypersensitivity compared with 20 patients with documented immediate hypersensitivity to penicillins recruited in Italy. Subsequently, we analyzed in silico Illumina Immunochip genotyping data that covered the HLA loci in 98 Spanish patients with delayed hypersensitivity and 315 with immediate hypersensitivity compared to 1,308 controls. The two alleles DRB3*02:02:01:02 and DRB3*02:02:01:01 were reported in twenty cases with delayed reactions (83%) and ten cases with immediate reactions (50%), but not in the Allele Frequency Net Database. Bearing at least one of the two alleles increased the risk of delayed reactions compared to immediate reactions, with an OR of 8.88 (95% CI, 3.37-23.32; p  We showed that the HLA-DRB3 locus is strongly associated with an increased risk of delayed penicillin hypersensitivity, at least in Southwestern Europe. The determination of HLA-DRB3*02:02 alleles in the risk management of severe delayed hypersensitivity to penicillins should be evaluated further in larger population samples of different origins

Elastase and exacerbation of neutrophil innate immunity are involved in multi‐visceral manifestations of COVID‐19

International audienceBackground Many arguments suggest that neutrophils could play a prominent role in COVID-19. However, the role of key components of neutrophil innate immunity in severe forms of COVID-19 has deserved insufficient attention. We aimed to evaluate the involvement of neutrophil elastase, histone-DNA, and DNases in systemic and multi-organ manifestations of COVID-19.Methods We performed a multicenter study of markers of neutrophil innate immunity in 155 cases consecutively recruited in a screening center, local hospitals, and two regional university hospitals. The cases were evaluated according to clinical and biological markers of severity and multi-organ manifestations and compared to 35 healthy controls.Results Blood neutrophil elastase, histone-DNA, myeloperoxidase-DNA, and free dsDNA were dramatically increased, and DNase activity was decreased by 10-fold, compared with controls. Neutrophil elastase and histone-DNA were associated with intensive care admission, body temperature, lung damage, and markers of cardiovascular outcomes, renal failure, and increased interleukin-6 (IL-6), IL-8, and CXCR2. Neutrophil elastase was an independent predictor of the computed tomography score of COVID-19 lung damage and the number of affected organs, in multivariate analyses. The increased blood concentrations of NE and neutrophil extracellular traps were related to exacerbation of neutrophil stimulation through IL-8 and CXCR2 increased concentrations and increased serum DAMPs, and to impaired degradation of NETs as a consequence of the dramatic decrease in blood DNase activity.Conclusion Our results point out the key role of neutrophil innate immunity exacerbation in COVID-19. Neutrophil elastase and DNase could be potential biomarkers and therapeutic targets of severe systemic manifestations of COVID-19

Methamphetamine-induced turning behavior in rats transfected with several plasmids.

<p>The plasmids were pCMV-TCII-OLEO coding for transcobalamin-oleosin (TO), pCMV-OLEO-TCII coding for oleosin-transcobalamin (OT), pCMV-TCII coding for transcobalamin II (T), pCMV-OLEO coding for oleosin (O), and pCDNA3 (P). The values are the mean±SEM of 3 animals per group. ** = Significantly different from control groups. <i>P</i><0.01, repeated-measures two-way ANOVA and Bonferroni post-test.</p

Apoptosis of tyrosine hydroxylase (TH) immunoreactive cells in the <i>substantia nigra</i> of rats transfected with several plasmids.

<p>A: TH-immunoreactive neurons after transfection. The neurons were transfected with NTS-polyplex with one of the following plasmids, pCMV-TCII-OLEO coding for transcobalamin-oleosin (TCII-OLEO, 1), pCMV-OLEO-TCII coding for oleosin-transcobalamin (OLEO-TCII, 2), pCMV-TCII coding for transcobalamin II (TCII, 3), pCMV-OLEO coding for oleosin (OLEO, 4), and the pCDNA3, the empty plasmid (5). Mesencephalon slices (40 µm) were immunostained at 2-month after transfection with a mouse monoclonal antibody to TH and a donkey antimouse IgG fluorescein labeled. Representative micrographs of sagital section of the rat mesencephalon are presented. Calibration bars = 200 µm. B: Apoptosis in TH-immunoreactive neurons after transfection with the plasmid pCMV-TCII-OLEO. Representative micrographs of the <i>substantia nigra</i> (with double immunostaining at 15-day after transfection) are presented. The primary antibodies were a mouse monoclonal antibody to TH, and a rabbit polyclonal antibody to cleaved Caspase-3. The secondary antibodies included a donkey anti-mouse IgG FITC labeled (1 and 4), and a donkey anti-rabbit IgG rhodamine labeled (2 and 5). Representative micrographs of coronal section of control <i>substantia nigra</i> (1–3) and transfected <i>substantia nigra</i> (4–6) of the same rat are presented. Scale bars = 50 µm. C: Apoptosis in TH immunoreactive neurons expressing the TCII-OLEO chimera. Representative micrographs of the <i>substantia nigra</i> with triple immunostaining at 15-day after transfection. The primary antibodies were a mouse monoclonal antibody to TH, a goat polyclonal antibody to TCII, and a rabbit polyclonal antibody to cleaved Caspase-3. The secondary antibodies were a donkey anti-mouse IgG AMCA labeled (1 and 5), a donkey antigoat IgG fluorescein labeled (2 and 6), a donkey anti-rabbit IgG rhodamine labeled (3 and 7). Representative micrographs of coronal section of control <i>substantia nigra</i> (1–4) and transfected <i>substantia nigra</i> (5–8) of the same rat are presented. Scale bars = 50 µm.</p